Evaporator and brine cooler



June 25,1929, T. SHIPLEY l.7l8.3ll

OOOOOOOOOOOOOOOOOOO OOO ER in Hil MUM T. SHIPLEY 1,718,311

EVAPORATOR AND BRINE COOLER Filed Jan. 21, 92? 5 Sheets-"Sheet 2 June 25, 192 9.

000 O0 000 q x v SRO: no 11-) completely flooded, or even approximately Patented June 25, 1929.

3 THOMAS snI'rLEY, or Y RK, rENNsYLvaNIA, assronon, BYnEsNE assrennmqrs,

T Yoaxrcn MACHINERY conroaarlron', or Yonx', rnnnsvnvam, A coarona- TION or pnnawann rivaroaa'roa Ann nanvaoootna' This invention relates to refrigeration,

and particularly to evaporators intended to I to sweep liquid refrigerant out with it and been found that there is be operated in a flooded condition.

An important feature ofthe invention is the application of forced circulation to the liquid refrigerantin suchevaporators. A'suother feature of. the invention the; application of thefforced circulation idea; to a special type of evaporator in'stallationQvin which the evaporator is installed ma oon-- fining duct through which brine to be chilled is circulated at a high velocity rate.

The advantages of flooded-operation are well understood, but difficulty has always been encountered in maintaining the coils so. Thisarises. particularly from the fact thatthe disengagement of the ammoniavapor does not take place-as freely as is desired, and there is a tendency for the vapor thus cause substantial portions of the evaporator to become gas bound. Much has been accomplished by improvements in the design of evaporators, but those forms which are most favorable to rapid disengagement of the gaseous refrigerant are expensive to construct and often they fail to meet all the requirements of the service. One difiicult is that as the transfer of heat is increase the tendency of the evaporator to become gas bound is greatlyincreased, with the consequent reduction of the effective area of the evaporator.

The high velocity circulation brine coolers above referred to, in which the brine in cont-act with the coils is of the 160 feet per minute, 'form of m and have demonstrated in practice highly successful operative characteristics, includ ing an unprecedented high heat transfer per square foot of evaporator surface. It is desired, however, to increase still further this heat transfer and efficiency. It has a tendency for the evaporator to become gas-bound when heavily loaded. This places a definite limit on the capacity of the evaporator. The present invention involves the use of a suction trap or its equivalent, preferably so related to the evaporator that it will feed velocity order of the subject matter liquid refrigerant to the evaporator and maintain the same flooded, in conjunction liquid refrigerant from the trap,

4 tion are illustrated prior application, Serial N 0. 106,165,

Application filedl'anuary 21, 19.27.- Serial No. 182,573.

with a. eir culating pump which will draw wardlythrough the evaporator, and deliver the liquid refrigerant, together with the vapor zed refrigerant derived therefrom, back into the suction trap w i I The invention further contemplates a bypass connection, by means of'which the circulatmg pump may be cut out of the, circulating system altogether, operate by; gravity. When the pump is in operation the lay-pass maybe used to vary force it up- .allowing this to the effectivecirculation through the evapo rator.-.' I

Two practical embodiments of the invenin the accompanying plan view of a bri ne tank, I show ng cans in place and'illustrating the drawings.

' Fig. -l is a top location of the circulators, the head box and highvelocity duct relativelyto the tank.

Fig. 2 is a view partly in elevation and partly in'longitudinal axial section through k the tank.

Fig. 3 is a fragmentary section on the line 3-3 of Fig. 2, looking inthe direction of the arrows, and drawn on a slightly enlarged scale.

Fig. dis a section on the' -linelH of Fig. 2, looking in the direction of the arrows.

- Fig. 5 is a diagrammatic representation of a'inodified form of the invention, in which the invention is applied to cold storage room coils. i

In Figs. 1 and 2 the central 'portion is broken away to indicate that the brine tank may be, and ordinarily is, longer relatively to its width than is shown in these figures.

The brine tank is indicated generally by the numeral 11. It is rectangular in form and is preferably-of greater length than width. The depth of the tank is preferably such as to leave only a small interval between the bottoms of the ice cans 12 and'the bottom 13 of the tank. While other arrangements are feasible, I refer and illustrate an arrangementin which the. high velocity duct, within which: the evaporator is of the brine flow through each can First, that it permits an even dis- 'mounted, extends longitudinally through the middle of the tank, dividing the tank into receiving portion of the tank, and, second, the .interval between the duct and the side of the tank is not too great to be spanned by the frame of a multiple can unit of ordinary size. The duct thus becomes a part of the can supporting structure and the interior of the tank is left clear of can supporting frame work.

The duct is best shown in Fig. 3. It consists of side plates 14 which are flanged and riveted to the bottom 13 of the tank. The side plates 14 are connected by,channels 15 which form the top and bottomof the duct. These channels are slightly inclined as shown. At the discharge end (the right hand end as viewed in Fig. 2) the duct terminates at 16 short of the end of the tank, so that brine discharging from this end of the duct, has an opportunity to discharge can receiving portions of the tank.

laterally in opposite directions into the two The upper edges of the plates 14 are reinforced by angles 17 and these extend from the head box to the right end of the tank, serving not only to brace the duct structure to the end wail of the tank, but also to support the ends of the frames of the can units.

The head box is at the opposite endof the tank, i. e., the left hand end in Fig. 2. The duct is tightly connected with the head box to which brine is pumped from the head end of the tank, and from which such brine flows to the head or inlet end of the duct. This head box, as is indicated in Fig. 4, is of inverted T-shape. The central portion, indicated generally by the numeral, 18, extends the full height of the tank 11 and is closed at thetop by a plate 19. This is necessaryas considerable pressure head is developed in the head box by the brine circulators. Projecting laterally from the central chamber 18 of the head box are lateral extensions 20, whosedepth is less than the depth of the tank. The central chamber 18 and the extensions 20 are formed of plates 21, 22 and 23, riveted to each other and to the walls of the tank. The top plate 22of each extension 20 is formed with an aperture in which is mounted the housing 24 of a brine circulator of any suitable type. In the drawing there is choseii for illustration a known type. of brine circulator which makes a use of a screw propeller 25 driven through aperture registering with the entrance end of the duct.

The bri'ne drawn from the head end of the tank by the circulators, passes by way of The frameimam extensions 20 and central chamberlS, to the duct, flows through this duct to the op posite end thereof and there discharges. The discharging brine divides into two streams, one of which returns through one side section of the tank and. the other through the other side section. The cans are mounted in the tank so as to leave a substantial interval 28 between the last can unit and the end of the tank, through which interval thebrine discharging from the duct flows laterally, thus insuring a relatively even distribution of the flow between the cans toward the head box.

The mounting of the cans is shown in Figs. 1 and 4. Each can unit comprises five cans 12, supported by a bar frame 29. Each can unit is filled and dumped as a group. The bar frames 29 extend beyond the ends of each group, one end being supported on the angle 17 and the other on an angle 30 riveted to the wall of the tanks (see Figs! 3 and 4). Any preferred mode of supporting the cans, either singly or in groups, might be adopted, but that shown is preferred becausethe removal of all the can units exposes the entire tank structure.

,The evaporator consists of two identical units each comprising a vertical top or offtake header 35, a horizontal bottom or supply header 36, and a plurality of tubes 37 connecting said headers. Each tube extends first vertically upward from the header 36 and is bent so that it extends through the duct at an inclination conforming to the inclination of the duct. The purpose of inclining the duct and the tubes, is to insure a relatively free disengagement of vapor in the event that-gravity circulation instead of forced circulation is availed of. This practice is intended to be followed during the periods of light load. I

The supply headers 36 are fed through a liquid refrigerant line 38 and manifold 39,

manifold 40 and oif-take pipe 41, larger than the pipe 38, into the suction trap 42. Here liquid and gaseous refrigerant separate and the gaseous refrigerant passes off through the suction line 43. The liquid refrigerant is fed to the trap 42 from the receiver 44 by way of dip pipe 45, anda float valve, consisting of a float chamber 46, float 47 and float controlled valve 48. The pipe 45 discharges liquid refrigerant through the valve 48 into chamber 46, and chamber 46 is in free communication. with trap 42 by way of pipe 49. There is a pressure equalizing connection 50 between the float chamber 46 and the suction trap 42 above the liqifid level therein.

to maintain the liquid level in the trap 42 slightly below the discharge end of the pipe 41.

The float 47 is preferably so adjusted as The structure so far defined conforms generally to one embodiment of the invention illustrated and claimedin my prior application above identified.

As in said prior application, there isa liquid line connection 51 which leads from the bottom of the trap 42 'to the pipe 38.

This connection is supplied with a stop valve 52. .A circulating pump '53 driven by a motor 54 is interposed in a by-pass around the valve 52. This by-pass' consists I flooded evaporator. If the valves 56 and 58 are opened and the pump 53 is operated, there is a forced circulation from the trap 42 through the pump :53 tothe bottomheaders 36 and thence through the tubes 37 to the top headers 35. From the top headers 35 the flow continues through the pipe 41 back to the trap 42. The rate of forced circulation may be varied by changing the speed of operation of the pump 53, or a simpler regulation may be had by adjusting the valve52. circulatory flow is had; If the valve be When this valve is closed a full opened more or less the circulatory flow is diminished because the valve 52 offers a circulating by-pass between the suction and discharge of the pump.

' The utility of forced circulation of the refrigerant is not confined to 'the brine cooler field.- In Fig. 5 the application of the invention to coolers for use in'cooling or hardening rooms is'illustrated. V

In this figure 61 represents the suction trap, 62 the suction line to the compressor, 63 is a float chamber, 64 a liquid supply line and 65 a valve controlling the supply of liquid refrigerant through the pipe 64 to the chamber 63, the valve 65 being controlled by a float 66. The chamber 63 has top and bottom connections 67 and 68 with thesuction trap 61. The evaporator is made up of an upper off-take header 69, a lower or supply eader 70, and a plurality of sinuous coils 71, of any suitable form. It is desirable that the coils be so formed as toavoid pockets in which be trapped.

The liquid refrigerant supply line from trap 61 is shown at 72 and leads through a valve 73 to the suction side of a-circulating pump 74. This discharges back through pipe 75 and,valve 76 to the supply header of the evaporator. A by-pass connection controlled by valve 77 is interposed between the pipes 72 and above the valves 73 and 76. If the valves 73 and 76 are closed and the valve 77 opened, the coils 71 may be operated partially flooded, but the preferred operation is to employ forced circugaseous refrigerant might a acts as'a by-pass between the pipes 75 "and72.

The structure shown in Figures 1 to 4 inclusive, involves not only forced circulation of the refri erant, but the conjoint use of forced circu ation of the refrigerant and brine in counterflow relation.

Where the counterflow arrangement is adopted, the warmest brine" first contacts with the discharge end of the evaporator, and the most violent evaporation of the volatile refrigerant occurs closely adjacent the vapor ofl'take. This reduces the flow path for the greater portion of the vapor generated in the evaporator. Thus the advantage is distinctly different from that secured by counterflow where a simple heat interchange between two liquids at'diflerent temperatures is sought. Remembering that in the present invention the refrigerant is circulated in a quantity in excess of that which can be evaporated in a single pass through the evaporator, the evaporation would occur wit the same heat absorbing effect at any point in the"evaporator. The desirability of the counterflow arran ement' arises not from the familiar counter ow heat exchange principie, but because of the greater freedom which is afforded for the discharge of the vapor.

An advantage of the invention in both forms of the device illustrated, is that at light loads it is possible to secure flooded operation without use of the circulating pump, and it is po's'sible'toicut the circulatmg pump into action atany time that forced circulation becomes desirable. In both forms of thedevice circulatory flow is in such direction as to be favorable to the Various other modifications of the inven the gas tion will suggest themselves to those skilled in the art, and are contemplated by me, the examples herein illustrated being designed as typical examples showing the commercial applicability of the invention.

I claiin: l

1. Ina brine cooler, the combination of a confining duct; an evaporator in said duct;

means for circulating brine through said duct at a velocity of the order of 160 feet 'per minute; and power driven circulatory means for circulating volatile liquid refrigerant through said evaporator in quantitygreater than evaporable in said evapo 'ator in a single passage'of thenliquid therethrough,

2. In a brine cooler the combination of a confining duct; an evaporator in said duct having refrigerant confining passages extending in the direction of the length of the duct; means for circulating brine through said evaporator, in counterfiow relation t said, duct at a velocity of the order of 160 feet per minute; and power driven means for circulating volatile refrigerant through c is said evaporator in a'direction from the lower header to the upper header in quantity in excess of that evaporable in a single passage through the evaporator; power driven means for circulating brine through the duct in heat exchanging counter current relation with the refrigerant flowin through the evaporator; means for Withdrawing vaporized refrigerant from the upper header;

and means for supplying liquid refrigerantto the evaporator. I

4. In a brine cooler the combination of a confining duct; power means for circulating brine through said duct; an evaporator in said duct having refrigerant confining passages extending in the direction of the length of the duct' and having a rising gradient toward the brine inlet end of theduct; an offtake connection leading from .theevaporator adjacent said'brine inlet end of the duct; a suction trap connected to said oiftake and located above said evaporator; a suction connection leading from said trap; a connection from the bottom of said trap to the end of said evaporator adjacent the discharge end of said duct; a circulating pump interposed '-in the last named connection and operable to draw volatile liquid refrigerant from said trap and discharge it to said evaporator and means for supplying refrigerant to the evaporator.

5. Ina brine cooler; the combination of a confining duct; power means for circulating brine through said duct; an evaporator in said duct having refrigerant confining passages extending in the direction of the length of the duct and having a rising gradient toward the brine inlet end of the duct; an oiftake connection leading from the evaporator adj acent said brine inlet end of th'e duct; a suction trap connected to said,offtake and located above said evaporator; a suction connection leading from said trap; a connection from the bottom'of said trap to the end of said evaporator adjacent the discharge end of said duct; a circulating pump interposed in the last named connection andoperable to draw volatile liquid refrigerant from said trap and discharge it to said evaporator; a valve controlled by-pass around said pump; and means for supplying refrigerant to the evaporator.

6. In a refrigerating system, the combination of a receiverand an evaporator connected to establish 'a closed circuit; power circulating means for circulating liquid refrigerant in said circuit;a valve controlled by-pass connecting the inlet and discharge of said power circulating means; a connection for withdrawing vaporized refrigerant from said evaporator; and a connection for supplying liquid refrigerant to said circuit.

7. In' a refrigerating system, the combination of a receiver and an evaporator con- 'nected to establish a closed circuit leading from the lower portion ofthe receiver to the bottom of the evaporator, thence upward through the evaporator and from the top of r the evaporator to the receiver; power-driven circulating means for positively circulating volatile refrigerant in said closed circuit;

a valve controlled by-pass conneeting the inlet and discharge of said power circulating means; a suction connection for withdrawing vaporized refrigerant through the top of the evaporator; and a connection for supplying liquid refrigerant to the circuit to compensate for that evaporated.

. In testimony whereof I have signed my name to this specification.

THOMAS SHIPLEY 

